Multiphase DC-DC power converters are used in many applications, such as for power supplies for personal computers, office equipment, laptop computers, and servers. The DC-DC converter produces a regulated output voltage (Vout) having a magnitude that differs from the input voltage received (Vin). For example, in a computer off-line power supply, a 120 V or 240 V AC utility voltage as the Vin is generally rectified to a DC voltage, then a DC-DC converter that implements switching reduces the rectified voltage to the regulated lower DC voltage required by the processor IC, such around 1 to 2 Volts.
It is common for DC-DC power converters to use same inductance values for each of its plurality of phases. However, the same inductance for each phase may not result in good power conversion efficiency, such as if one needs higher efficiency over a wide load range from light load operation to heavy load operation (e.g., in data center applications) where the loading of the microprocessors can be random based on its Internet client' utilizations across the whole world.
It is known that smaller inductance value inductors provide a faster converter transient response, and that larger inductance values inductors have lower AC losses which provides higher efficiency at light load conditions. A dynamic phase shedding (DPS) concept is known which involves turning completely off one or more of the DC-DC converter's phases which can be employed to reduce the power consumptions at light load conditions.